import java.util.Scanner;

public class Main1233 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < arr.length; i++) {
            arr[i] = sc.nextInt();
        }
        for (int i=0;i<arr.length;i++){
            for (int j=i+1;j<arr.length;j++){
                if (arr[i]>arr[j]){
                    int temp=arr[i];
                    arr[i]=arr[j];
                    arr[j]=temp;
                }
            }
        }
        int a = n / 2;
        int b = n / 2 - 1;
        double s = 0.0;
        double s1 = 0.0;
        for (int i = 0; i < arr.length; i++) {
            if (n % 2 == 0) {//偶数
                s = arr[a] + arr[b];
                System.out.println(String.format("%.1f", s / 2));
                break;
            }//奇数
            s1 = arr[a];
            System.out.println(String.format("%.1f", s1));
            break;
        }
    }
}
